Aircraft door



J. B. CASTLE AIRCRAFT DOOR Feb, 21, 1950 2 Sheets-Sheet 1 Filed Dec. 27, 1944 I N V EN TOR. J mBLazr/le BY Z Z5 ANN Faisal/WW Feb, 21, 1950 CASTLE 2,498,527

AIRCRAFT DOOR Filed Dec. 27, 1944 2 Sheets-Sheet 2 INVENTOR.

CrlJ'lle BY 2 Patented F eb. 21, 1950 rem 'FFICE AIRCRAFT noon John B. Gastle, Los Angeles, Calif., .assignor to Douglas Aircraft Company, 'Inc a corporation of Delaware Application December 27, 1944, Serial "No. 570,025

8- Claims.

The present invention relates to doors and hatches and more particularly to improvements in door latch control units for doors and hatches oi the'type used in aircraft.

.As the fuselages of aircraft become fully enclosed, and as air-craft of greater size and weight are built, there has arisen the necessity for pro viding a plurality of emergency exit, cargo disposal, and other openings in Various compartments and portions of the airplane, and for providing these openings with suitable doors or hatches. It has heretofore been the practice to design the individual doors tosuit the required openings and to have the latchcontrol unit built into the door in such manner as to meet the specific needs of the particular installation. This prior method requires considerable detail assembly work in fitting the individual parts together on the door and has resulted in high manufacturing costs and reduced production. These objections have been eliminated or minimized to a considerable degree by the present invention which comprises a door latch control assembl of a novel, unique and interchangeable type arranged'to meet the design requirements of a plurality of doors, being provided in a control unit such that it maybe installed on the door merely by riveting or bolting to the door structure.

struction, A further object resides in providing such a latch control unit in which one or a plu- 1 rality of latch rods can be connected to and 0pera'ted from the control unit, the number depending upon the design requirements of the particular application. A further object comprises the provision of a latch control unit which will remain in its positively locked position and in which any motion on the latch bolt will have no tendenc to unlock the latch. A further objiect is directed to providing such a unit of considerable utility which is easily manufactured and is i such that the'latch rods'can be readily attached to the unit. A still further object of the "invention resides in the provision in a door latch con- 'trol unit of the-present type of an adjustment and stop for the throw of the crank to which the latch rods are attached. :Other objects and, advantages of the present invention will become apparent to those skilledin the art gaiterra readinaef the present description together with :the accompanying .drawiings 'iorminga .parthereof, in which;

Ill

Fig. 1 is a partial side elevation of an aircraft door to which the control unit of the present. invention is shown adapted;

Fig. 2 is a sectional elevation of Fig. .1 taken along-the lines 2-'2 thereof;

Fig. 3 is a sectional view of the door taken along the lines .l3 of Fig. 1;

Fig. 4 is an elevational view of the doorlatch control unit as viewed in Fig. 1;

Fig. 5 is a sectional view of the control unit as taken along the lines 5--5 of Fig. 4;

Fig. 6 is a cross-sectional View as taken along the lines 5-5 of Fig. 4;

Fig. 7 is a sectional View of the control unit as taken along the lines l--'! of Fig. 6; and

Fig. 8 is a sectional view taken alongthe lines 3& of Fig. '7 showing the latch actuating spring mechanism.

Referring now to Figs. '1, 2 and 3, the numeral it indicates a typical door or hatch to which the present invention has been shown and described as a typical adaptation. The door iii whichhas been selected for descriptive purposes only, is shown as an emergency exit of the readily removable type in the sidewall of an aircraft fuselage. It is accordingly shown with appreciable curvature in its lower half in the direction of its vertical height, whereas across its width it is relatively straight. It will be understood that the present invention is not limited to removable doors or hatches of the type shown but may be used upon fixed or hinged doors of a wide variety of shapes, in planar, double, or multiple curvature walls. The present door is shown as made up of outer and inner wall panels l i and !2, respectively, carried upon a frame structure The central portion of the door is preferably provided with a fiat supporting plate section M spaced intermediate the planes of the outer and inner panels. The plate i It forms the support for the novel door latch control unit 55 of the present invention, being bolted, riveted or otherwise attached thereto.

The latch control unit it consists essentially of inner and outer identical housing plates lfi'and I l,.placed face to face and interconnected by fastening screws it as more particularly shown in Figs. 4. to 7. inclusive. The central portions of the housing plates it and ii are suitabl bored for the hollow shaft l 9 and the bushings or bearings 2t. Suitable operating handles 33! and 22 are attached to the inner and outer ends of the hollow shaft is as by the pins A spider or multiple crank member 2% is also suitably bored to receive the shaft i 9 to which it is attached as by the .pin .25. The spider 24 is provided with aplurality of crank arms 26, 21, 28 and 29 extending radially from its axis of rotation of the shaft 19 and spaced rotationally 90 degrees apart. The crank arms 26, 21 and 23 are tongue-shaped to receive the bifurcated terminals of the clevises 30 to which they are attached by the pins 3|. The crank \arm 28 is bifurcated and apertured to receive between its bifurcations a pinched clevis terminal 32 and an eye-bolt 33 to which it is at tached by a similar pin 3|.

The eye-bolt 33 provides the connection between the fixed supporting plates l6 and I! and the rotatable spider 24 for the spring mechanism whereby the door is maintained either in its latched or unlatched condition. The eye-bolt 33 has a flat tongue portion connected by the pin 3| to the bifurcated crank arm 28 as indicated above, and is free to reciprocate through the opening 34a in the trunnion fitting 34 which in turn is provided with extending pin portions 35 adapted to be journalled in aligned apertures within the plates [6 and ll. of the eye-bolt 33 is embraced by a coiled compression spring 31 and the outer terminal of the shank is threaded to receive a lock-nut 36 for adjusting the extended length between the pivots 3! and 35 to thereby define the limits of throw of the crank 24.

Referring again to Figs. 1 to 3, inclusive, it will be noted that the outer terminals of the arms 26, 27, 28 and 29 of the crank spider 24 are suitvably pinned as at 3i to the several clevises 30 which in turn are connected to the actuating rod links 38 extending out to the beveled latch tongues or bolts 39 at the jambs of the door or hatch. The horizontally extending actuating rods 38 can either be straight or slightly bent as shown in Fig. 3 for the rectilinear actuation of the latches 39 through the suitably apertured frame members I3 and the adjacent pivoted rollers 40, adjacent to which there is provided a suitable jamb seal strip 4!. In the curved or vertical direction of the door, the actuating rod is preferably coupled as at 42 and a curved guide ,tube 43a provided between the rigid guide clips 43 suitably bolted to the door structure, suitable access openings being provided as at 431) in the inner wall plate l2. The recessed portion at the center of the door on the outside of the flat mounting portion M is preferably provided with a faired cover portion 34, hinged at Ma. The cover is actuated by a suitable latchin-g device 45 whereby the cover 44 can be released and hinged back or removed in order that an operator from the outside of the airplane is afiorded access to grasp the outer handle 22 and latch or unlatch the door.

It will accordingly be seen that rotation of the inner handle 2| and spider 24 as shown in Figs. 1 and 4, in a clockwise direction, will cause compression of the spring 31 co-axially mounted upon the shank of the eye-bolt 33, together with concurrent rotation of the arm 28 to which it is pivotally attached, as well as the arms 26, 27 and 29 pivotally attached to the remaining latches. As the arm 28 is rotated beyond its dead center or intermediate position in radial alignment with respect to the trunnion pivot 35, further compression of the spring 3? ceases and the spring expands into its position as shown in Fig. 7 in which it maintains the position of the attached crank arms in the unlatched condition of the door latches. The spring 31 is assembled with initial compression such that it tends to separate the pivots 3i and 35 in both of the posi- The shank portiontions shown in Figs. 4 and 7 and thereby maintains the latches in the extreme positions, namely either fully latched or fully unlatched. The said separating tendency of the spring 37 is adjustably limited by the setting of the lock-nut 36 which accordingly acts both as a stop and an adjustment means. This adjustment must be such that in the latched position the rods and the arms are either aligned or rotated slightly beyond the aligned position in which motion of the latch bolt will have no tendency to unlock the latch. The latch mechanism 45 for the handle access cover 44 may preferably be of the type shown in Patent No. 2,337,531 which issued to Alfred C. Stockton on December 21, 1943.

Each of the cranks 26, 21, 28 and 29 is preferably of the same radius and in the particular modification shown, which has been found extremely satisfactory in actual service, the throw of the outer pins 3! between the extreme positions of Figs. 4 and 7, is somewhat greater than the radius of the arms as they are passed through their approximately degree path of rotation. Accordingly in this design, in the event the crank does not rotate through its full 110 degree path, the crank arm must be longer to obtain the same throw, and if the crank is made longer, the spring assembly must also be longer, resulting in a larger unit to serve the same purpose. It has been found that the relatively small radius crank makes the latch operate easier because of the shorter lever arm. It will accordingly be seen that the disclosed invention provides a latch device of extreme simplicity which is adjustably adaptable to many installations. It is relatively inexpensive to produce inasmuch as the machine work is almost entirely absent from its manufacturing operation. Other advantages and uses of the present invention, which will become apparent to those skilled in the art, are intended to fall within the scope and spirit of the invention as more particularly set forth in the appended claims.

I claim:

1. In a door structure, means for controlling a plurality of door latch bolts comprising a pair of plate elements, a multiple crank element coaxially mounted with said plate elements upon a shaft member extending through said door structure, means interconnecting said crank element with said latch bolts, variable length means pivotally interconnecting said crank and plate elements and resilient means arranged to oppose variation of said variable length means adapted to urge said crank element into its ex treme latched and unlatched positions.

2. An aircraft door arrangement for a body having an opening therein, a door structure adapted for fixation within said opening, an apertured plate element attached to said door structure, a shaft element passing through and journalled within the aperture of said plate element, handle means attached to the terminals of said shaft element, a spider element attached to said attached to said door structure, a shaft element journalled within said plate elements and passing through a wall of said door structure, means attached to the terminals of said shaft element for the latching and unlatching rotation thereof, a spider element including a plurality of crank arms fixedly attached to said shaft element intermediate said plate elements and stop means comprising alink pivotally mounted between one of said crank arms and said plate elements and a spring arranged to resiliently separate the pivotal mountings of said link the said stop means in cooperation with said spring developing a toggle effect adapted to both urge said latches into their extreme positions and to define the said extreme positions.

4. A latch control unit for a door structure provided with a plurality of latching bolts, a manual actuating assembly comprising a shaft element and attached handle elements rotatably journalled upon said door structure, a multiple crank element fixedly attached to said shaft element for rotation therewith and pivotally interconnected with each of said latch bolts, a variable length mechanism p-ivotally interconnecting said multiple crank element with said door structure, said mechanism including a compression spring to resiliently oppose shortening between said pivots and adapted to urge said latch bolts into their extreme positions, said mechanism also including adjusting means to limit the lengthening of said mechanism and thereby to define the said extreme positions of said latch bolts.

5. In a door latch control unit of the type which includes a handle-rotated spider pivotally interconnected with a plurality of latch bolts for their reciprocating actuation, a positive acting assembly for determining the limits of said latch bolt movements and to urge the same into their limiting positions comprisingan eye-bolt element pivotally attached adjacent a first terminal to an arm of said spider and guided through a trunnion pivotally mounted upon the door structure adjacent an opposite terminal of said eye-bolt, resillent compression means interposed between said inner terminal and said trunnion and an adjusting nut threadedly engaging the shank of said eye-bolt beyond said trunnion.

6. In a door latch control unit of the type adapted for the rectilinear actuation of a plurality of latch bolts, including a handle-actuated multiple crank member pivotally interconnecting said latch bolts and mounted for rotation upon an axis normal to the general plane of said door and toggle actuating means including a bolt-like 7. In a door latch control unit of the type adapted for the rectilinear actuation of a plurality of latch bolts, including a handle-actuated multiple crank member pivotally interconnecting said latch bolts and mounted for rotation upon an axis normal to the general plane of said door and toggle actuating means including a boltlike element pivotally interconnecting one of said crank arms and reciprocable through a trunnion element pivotally rocking on an axis spaced from and parallel to said multiple crank axis, spring means interposed between said pivotal connections adapted for the resilient separation of said pivotal connections and the resilient urging of said latch bolts into their extreme positions, said toggle actuating means including adjustment means adapted to determine the limits of said extreme positions, said latch bolts reciprocable element pivotally interconnecting one of said crank arms and reciprocable through a trunnion element rocking on an axis spaced from and parallel to said multiple crank axis and spring means interposed between said pivotal connections adapted for the resilient separation of said pivotal interconnection and said trunnion axis and the resilient urging of said latch bolts into their extreme positions.

within separate planes angularly disposed with respect to the general plane of said door, and universal means associated with the said pivotal interconnection between said crank member and said latch bolts arranged to facilitate said actuation within said separate planes.

8. In a door structure, means for controlling a plurality of reciprocating latch bolts comprising a member fixedly attached to the door structure, a bearing portion carried by said member, a shaft member supported within the said bearing portion of said fixed member, a multiple crank member mounted upon said shaft member for rotational movements with respect to said bearing portion, rod means interconnecting said multiple crank member with said latch bolts and toggle link means pivotally interconnecting said multiple crank member and a pivot axis fixedly disposed withrespect to said door structure, said toggle link means including a compression spring opposing shortening of said toggle link means arranged to urge said crank member ofi its dead center into its extreme latched and unlatched positions, and means for adjusting the length of the said toggle link means to establish the limits of said latched and unlatched positions.

JOHN B. CASTLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,580,666 Hansen Apr. 13, 1926 1,709,459 Callahan Apr. 16, 1929 1,929,341 Wegner Oct. 3, 1933 2,172,169 Claud-Mantle Sept. 5, 1939 2,354,297 Ayres July 25, 1944 FOREIGN PATENTS Number Country Date 661,660 Germany June 24, 1938 

